Experimental Study On Reinforced Concrete Beams Strengthened With Enlarging Section And Bounded Prestressing

With the rapid development of economic construction, there is a higher demand to the safety,applicability, durable of the building.In order to meet the needs of people, many building which don’t fit development requirements need to re-transformation,strengthening and maintenance. It can shorten construction period,save investment and do not take up new farmland. Structure strengthening has been a new subject in Engineering Application and Study, the study of structural strengthening technology has been becoming a research hotspot in both domestic and overseas.Nowdays the structural strengthening usually choose only one method. However, engineering practice shows that if only use one method there usually don’t have a good effect. In order to achieve the purpose of complementary advantages, several methods were chosen to strength structural. Reinforced concrete beams strengthened with integrated strengthening technique of enlarging section and bounded prestressing.It is called enlarging section and bounded prestressing strengthening methodAt the base of the testing research,this thesis study the stress mechanism and the failure modes of the strengthened beams.The experimental research showed that the strengthening of enlarging section and bounded prestressing was a positive strengthening method of which improved the utmost bearing capcity,strengthening effect was very perfect.The stress of the strengthened beam are divided into three stages, pre-cracking, from cracking to prestressing tendons yield and from prestressing tendons yield to concrete crushing.Through calculation and analysis,the simple calculation models of ultimate load-carrying capacity was proposed,and the prediction results from this model argee well with the testing. And it provide the reference and basis for engineering designing.